1. Field of the Invention
This invention relates to mufflers for reducing the exhaust noise of exhaust gases of internal combustion engines, and in particular for a muffler for a high output, high speed diesel engine.
2. Description of the Prior Art
When pure exhaust noise for a high output, high speed diesel engine must be below 78 to 80 dB (A), measured fifty feet from the source, the firing frequency and low order harmonics must be considered. The high sound pressure levels at these frequencies, which range from 100 to 300 Hz for high output, high speed diesel engines are a problem. Conventional mufflers, due to the relatively small volume allowed by space restrictions, do not reduce the low frequency noise effectively or if they do, the back pressure imposed on the engine is too great.